Re: Contributing LLVM.org patches to gud.el

[Eli Zaretskii]

> Date: Tue, 10 Feb 2015 19:47:15 -0800
> From: Daniel Colascione <address@hidden>
> CC: address@hidden
> 
> What exactly are the DWARF deficiencies that prevent a debugger from
> unwinding caller-saved registers to their original values? The
> specification seems more than powerful enough for the task.

In a recent enough GDB, those cases where you see <optimized out> are
not about caller-saved registers.  They are about variables whose
location at the current value of PC is not recorded in DWARF info in a
way that a debugger can use to glean their values.

You can read more about this in the discussion which started here:

  http://cygwin.com/ml/gdb/2014-09/msg00068.html